Abstract: A power supply for generating polarizing voltages for the drivers on an electrostatic speaker system includes a charging circuit which charges a battery from the applied audio signal. A dc-to-dc converter generates the relatively high polarizing voltages from the battery voltage and it includes an oscillator which generates an alternating voltage to a voltage multiplier circuit. An electronic switch circuit turns the oscillator on when an audio signal is present and turns it off a preselected time interval after the audio signal is removed.

Abstract: A quadraphonic headphone including an ambience control circuit which is contained within a hand sized case which is connected to the audio transducers in each headphone cup and which may be connected to a source of quadraphonic program material. The control circuit includes switches that allow the user to select the desired cross coupling of phase shifted audio signals between left and right primary audio transducers and left and right secondary audio tranducers, allows him to reverse the connections to any one of the audio transducers and allows him to sum the signals applied to the left or right audio transducers. The effect of this electronic mixing is enhanced by asymmetrically mounted the audio transducers within each headphone cup.